The espionage storm engulfing Formula One developed greater force at Silverstone yesterday. Details emerged of the documents involved in the allegations, and the two alleged protagonists that were said to have been seen in the private conversation some weeks ago.

A brief resume of the controversy so far. A British engineer, Nigel Stepney, is the subject of an Italian police investigation instigated by Ferrari, his former employers, who have subsequently fired him.

It is alleged that Stepney, who has denied any wrongdoing, passed confidential information about the team to a senior figure at McLaren. The British team have suspended an employee, but declined to name him. It is widely believed that he is Mike Coughlan, the team's chief designer.

In a fresh development, a senior member of another team yesterday claimed that he had seen Stepney and Coughlan in conversation between races earlier in the year. The pair were talking in a cafe at a marina near Barcelona on April 28. Of course, there is no reason why the pair should not have been discussing entirely innocent matters: everyone in F1 knows everyone else.

Further details also emerged of the documents supposedly involved, which are said to have been passed to the McLaren employee last April. The website of the respected German magazine Auto Motor und Sport claimed that this was not a case of a couple of electronic blueprints, but a photocopied 500-page dossier covering many aspects of Ferrari's racing operations.

The magazine said that the documents detailed designs and data relating to this year's Ferrari F2007, as well as details of the structures and processes employed at the Italian team's Maranello factory, information about important engineers, data regarding the set-up and preparation of the cars for a race weekend, quality control protocols, data from test sessions, and development plans for the future.

It was also claimed last night that Ferrari were alerted to the existence of the photocopied dossier by an alert employee at a photocopying company near McLaren's base in Woking.

What might all this mean? F1 is a sport in which the compulsion to gain a technical edge over rivals extends to the size and complexity of the teams' catering facilities. So at first glance, the passing of such material from one top team to another might be expected to be a matter of tremendous importance.

But wise heads in the paddock counselled caution. "Obviously I can't comment on the specifics of the case," said Mike Gascoyne, technical director of the Spyker team. "But look at it in general terms. McLaren are a very professional team, very experienced. They have been around for 30 years and they have been winning races very recently. The sort of things that these documents are supposed to describe... McLaren will have their own ways of doing them."

As Gascoyne pointed out, F1 teams develop in their own ways and at their own pace, and a team such as McLaren have faith in their own philosophies and approaches. They are also a notably moralistic outfit, and the team chief, Ron Dennis, is a man of stern principles. "Knowing McLaren, and their management, I simply can't see them condoning anything like this," Gascoyne said. "To me it makes no sense."

Which certainly did not stop the other inhabitants of the paddock trying to make sense of it. One sage pointed out that personnel swaps between teams happen all the time, and that managers are constantly on the lookout to poach talented individuals from their rivals.

At any one time, some of the best brains in the sport will be on "gardening leave" to supposedly prevent them from taking vital knowledge with them when they move down the pit lane. The kind of information supposedly involved in this case moves from one team to another on an annual basis, concealed in engineers' skulls. Furthermore, a small army of photographers and journalists spend every other weekend engaged in minute scrutiny of the cars in the pit lane and on the track.

If you want to know the latest about Ferrari's new winglets or Renault's innovative fins, you pick up Autosport and examine the work of Giorgio Piola, Mark Hughes and Gary Anderson. It is gobbledygook to a normal human being, but there will not be a designer in the paddock who does not consult those pages on a fortnightly basis.

F1 has had an undercurrent of intrigue and rumour ever since the sport was invented. It is what makes the paddock such a stimulating place. The sport is fuelled by gossip, and some of the tales being peddled this weekend are so Machiavellian as to make Alastair Campbell's hair stand on end. It would not be wise to pass them on, but there is nothing to stop readers using their imagination.

Meanwhile, as the inhabitants of this incestuous little world whisper and point fingers, back on the real planet fans are gathering who are interested in racing, not rumours. The camp site, renamed Hamilton Fields, is filling up with tents and caravans far less glamorous than those in the paddock. The inhabitants of the humbler vehicles have come to see their new hero race and - they hope - win. And stuff all the gossip.